The invention relates to an analysis chain or line designed for performing in an automated manner analyses, such as chemical analyses, on liquid samples contained in jugs.
Such an analysis chain can in particular be used in the nuclear industry for periodically checking the characteristics of certain products in a production or reprocessing plant without causing any risk for personnel or for the environment.
FR-A-2 675 582 describes an automated installation making it possible to take liquid samples at different points of a nuclear plant, introduce the samples into jugs and transfer the latter into analysis units or boxes by means of a pneumatic transfer system controlled by a central control unit.
FR-A-2 675 902 describes a device usable in such an automated installation for taking liquid samples and automatically introducing them into sealed jugs permitting their transfer to analysis units.
The existing installations, more particularly illustrated by the aforementioned documents, permit the automatic performance of sampling operations and the transfer of the jugs into the analysis units. However, the different operations which are then performed within the analysis units are carried out manually with the aid of remote handling grippers or tongs by operators located behind the windows equipping the analysis units. The protection of the personnel is ensured both by a complete sealing of the analysis units, which prevents the migration of contamination to the outside, and by shields protecting personnel against irradiation.
However, the manual performance of the different operations which have to be carried out in such analysis units causes numerous disadvantages which will now be described.
A first disadvantage relates to the identification of the jugs. Thus, the identification takes place by the operator through a very thick and therefore highly deforming window. Moreover, the identification relates to jugs which drop loosely into the bottom of the analysis unit when they reach the latter. This problem leads to an error risk and even to the loss of certain jugs. This often leads to operators requesting supplementary jugs and therefore increases the quantities of liquid and solid waste.
Another disadvantage relates to the unsealing of the jugs with the aid of remote manipulation grippers. This operation is particularly difficult and leads to a loss of time and to a risk of the content being poured into the bottom of the analysis unit.
It is also impossible to reseal the jugs with the aid of grippers in the analysis unit. Consequently it is impossible to recover surplus liquid samples or this can only be envisaged by creating a costly and complicated gravity collection system within the framework of existing equipment.
Other disadvantages result from the use of a conventional laboratory pipette for taking the samples necessary for analyses from the jugs. Thus, this procedure involves taking for each analysis a relatively large liquid quantity (at least 2 ml), which leads to a large liquid effluent volume. In addition, it is virtually impossible to perform several analyses on the basis of the same jug, which also considerably increases the quantities of solid and liquid waste. Moreover, a large quantity of chemical reagents is used, which increases operating costs. Finally, the analytical chemical reagents constitute disturbing ions, whose large quantity is very prejudicial with respect to the treatment of the effluents and/or a possible recycling.